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No. You cannot put any battery into a solar light. Most batteries will ruin your light.
I learned this the hard way. My solar path light died after two years. I opened the battery compartment. Saw a AA sized battery. I grabbed a regular alkaline battery from my drawer. The copper top one. Popped it in. The light turned on that night. I felt smart.
Three days later, the light stopped working. Would not turn on. Would not charge. Nothing.
I killed it. The alkaline battery ruined the charging circuit. I had to throw away the whole light.
So let me save you from doing the same thing.
Solar lights need rechargeable batteries. Alkaline batteries will destroy them.
Solar lights work on a simple cycle. During the day, the solar panel sends a small current into the battery. That current charges the battery. At night, the battery sends power to the LED.
Alkaline batteries are not designed for this. They are single use. You cannot recharge them. When the solar panel tries to push current into an alkaline battery, bad things happen.
The battery leaks. Acid comes out of the metal casing. That acid eats the battery contacts. It eats the circuit board. It eats the wires.
Even if the battery does not leak immediately, it will not charge. You get one night of light. Maybe two. Then the battery dies completely. And your light may die with it.
The only safe batteries are rechargeable Ni-MH or Li-ion
Ni-MH stands for nickel metal hydride. These are the silver colored rechargeable batteries. They cost 2to3 each. They handle being charged and discharged hundreds of times.
Li-ion stands for lithium ion. These are usually flat or cylindrical batteries. They are common in newer solar lights. They hold more charge. They last more years. They cost 5to10 each.
Every solar light comes from the factory with one of these two types. Look at the battery that came with your light. Match that type when you replace it.
Do not guess. Do not experiment. Match the type.
What happens if you put a regular alkaline battery in a solar light
I talked to a repair guy who fixes solar lights. He sees this mistake all the time. Here is what he told me.
The first night, the light works fine. The alkaline battery has plenty of power. You feel good.
The second day, the solar panel tries to charge the alkaline battery. The battery gets warm. Then hot. The pressure builds inside the metal casing.
By the third day, one of three things happens. The battery leaks acid. Or the charging circuit burns out. Or the battery swells and gets stuck inside the compartment.
In all three cases, your solar light is dead. The repair guy says he cannot fix lights damaged by alkaline batteries. The acid eats too many parts. Cheaper to buy a new light.
What about rechargeable alkaline batteries? Do not use those either.
Some stores sell rechargeable alkaline batteries. They look like regular copper top batteries but say rechargeable on the label.
Do not use these in solar lights.
Rechargeable alkaline batteries are designed for low drain devices like TV remotes and wall clocks. They do not handle the constant charge discharge cycle of solar lights. They die after 20 to 30 cycles. A solar light cycles every single day.
Ni-MH batteries handle 500 to 1000 cycles. Li-ion handles 800 to 2000 cycles. Use those.
Check the voltage before you buy a replacement battery
Most solar lights use 1.2V batteries. That is the standard for Ni-MH. Some use 3.7V lithium batteries. Read the label on your old battery.
Do not put a 1.2V battery into a light designed for 3.7V. The light will be dim. It will not charge correctly.
Do not put a 3.7V battery into a light designed for 1.2V. You will fry the circuit immediately. Smoke. Smell. Dead light.
Match the voltage exactly.
AA and AAA are the most common sizes for solar lights
Open any solar path light and you will find a AA or AAA battery inside. These are the standard sizes.
AA is thicker and taller. AAA is thinner and shorter. They are not interchangeable. A AAA battery rattles around in a AA slot. It does not make good contact. The light works poorly or not at all.
Stick to the same size that came with your light.
Some solar lights have built in batteries you cannot replace
Cheap solar lights from discount stores often have sealed batteries. The battery is soldered to the circuit board. No compartment. No door. No way to open it.
When that battery dies, the whole light dies. You cannot replace it unless you know how to solder. Most people just throw these lights away.
Before you buy a solar light, check for a battery compartment. If there is no obvious door or screw, the battery is sealed inside. Avoid these lights if you want your light to last more than two years.
How to find the right replacement battery for your solar light
- Step one. Open the battery compartment. Pull out the old battery.
- Step two. Read the label. It says Ni-MH or Li-ion. It says AA or AAA or 18650 or 14500. It says 1.2V or 3.7V.
- Step three. Buy a battery with the exact same words on the label. Same type. Same size. Same voltage.
- Step four. Insert the new battery. Make sure the plus and minus signs match the markings in the compartment.
Close the compartment. Put the light in the sun for two days. It should work like new.
What I do to make my solar light batteries last longer
I have six solar path lights. I replace their batteries every two years. Even if they still work. This costs me $12 total. Cheap insurance.
I also take the batteries out during winter. I live in a cold place. Freezing temperatures kill battery life. I store the batteries in my kitchen drawer. In spring, I put them back in the lights.
I clean the battery contacts with a pencil eraser once a year. Corrosion builds up over time. The eraser removes it. The light makes better contact. It charges better.
Do these three things and your solar light batteries will last three to four years instead of two.
The one exception to the rule. Some lights use 1.5V lithium batteries.
A few high end solar lights use 1.5V lithium primary batteries. Not rechargeable. These are expensive. They last for years. When they die, you replace them with the same 1.5V lithium battery.
How do you know if your light uses these? The manual says do not recharge. The battery says lithium. There is no solar panel wire going to the battery. The light uses a separate solar panel to charge a different battery inside.
This is rare. Most solar lights use rechargeable Ni-MH or Li-ion. If you are not sure, look at your old battery. Match whatever came out.
The bottom line after killing one light and fixing many
I killed one solar light with an alkaline battery. I learned my lesson. Now I keep a pack of Ni-MH rechargeable batteries in my drawer. Four AA and four AAA. Cost me $10. They work in all my solar lights.
Do not use alkaline. Do not use rechargeable alkaline. Do not mix sizes. Do not mix voltages. Do not guess.
Read the label on your old battery. Buy the exact same type. Your solar light will last for years.
Ignore this advice and you will be back at the store buying a new light. I know because I was that guy.
FAQs
Can I use a regular Duracell or Energizer battery in my solar light?
No. Regular alkaline batteries are not rechargeable. The solar panel will try to charge them. They will leak acid and destroy your light.
What happens if I put an alkaline battery in a solar light by mistake?
The light may work for one or two nights. Then the battery leaks or the charging circuit burns out. Your light will stop working permanently.
What type of battery do solar lights use?
Most use Ni-MH (nickel metal hydride) rechargeable batteries. Some newer lights use Li-ion (lithium ion) rechargeable batteries. Check your old battery for the label.
Can I use a higher mAh battery in my solar light?
Yes. mAh means milliampere hours. It tells you how much energy the battery holds. A higher mAh battery gives you longer run time. Just match the voltage and battery type.
Can I use a 1.5V rechargeable battery in a solar light that came with a 1.2V battery?
No. The charging circuit expects 1.2V. A 1.5V battery may overcharge or damage the circuit. Stick to the voltage printed on your old battery.
How long do solar light batteries last before needing replacement?
Ni-MH batteries last 2 to 3 years with daily use. Li-ion batteries last 3 to 5 years. Replace them when your light runs shorter hours than before.
Can I replace a built in soldered battery in my solar light?
Only if you know how to solder. Open the light. Desolder the old battery. Solder a new one in its place. Most people just buy a new light.
Why does my solar light need a rechargeable battery?
Because the solar panel charges the battery every day. A rechargeable battery is designed for this cycle. A regular battery is not.
Can I use a battery with a different size in my solar light?
No. AA and AAA are different sizes. They do not fit correctly. A loose battery makes poor contact. Your light will flicker or not work at all.
Where can I buy replacement batteries for solar lights?
Any store that sells batteries. Look for Ni-MH rechargeable batteries. Check the size. AA or AAA. Check the voltage. 1.2V is standard. Do not buy alkaline.
Summary
No. You cannot use any battery in a solar light. Only rechargeable Ni-MH or Li-ion batteries work. Regular alkaline batteries leak acid and destroy the light. Match the battery type, size, and voltage exactly. AA and AAA are common sizes. 1.2V is standard for Ni-MH. Replace batteries every 2 to 3 years. Do not use rechargeable alkaline batteries. If your light has a sealed soldered battery, you cannot replace it without soldering. Read the label on your old battery. Buy the exact same type.
